Riding mower platform



FIG. 1 is a right front perspective view of a riding mower platform showing my new design;

FIG. 2 is a left side perspective view thereof;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a front elevational view thereof.

The broken line showing of additional riding mower components is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a riding mower platform, as shown and described. 